VHF antenna - where?

zoidberg

zoidberg

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Yes, I know the preferred position is at the masthead, and I know why. Yet, I've sailed on many boats with non-functioning VHF/RT 'cos of a dicky antenna coupling 'up there somewhere' which will be fixed 'sometime'.....

The other option is mounted on the pushpit rail, or on a stub secured there that lifts the antenna a couple of metres higher. At present, that's my favoured option, principally as it would be readily accessible for 'maintenance'.

I DO have two new good quality antennae and a long length of quality cox, courtesy of our friend and contributor SaltyDog Salty John.
Also, my mast is down ATM.

Arguments pro and contra, please....?
 
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masthead. Pro- range, Con- difficult to service that one time in 20 years it fails because you didn't inspect it last time you had the mast down.
Anywhere else Pro- easy to reach, Con the primary reason for having an antenna is to communicate at distance.

If you are not mounting it on the mast head you may as well use a handheld or a loud hailer!
 
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Buck Turgidson said:
If you are not mounting it on the mast head you may as well use a handheld or a load hailer!
Click to expand...

If I don't have anything to say, I try not to say it.

I DO have a handheld, which is more efficient used in the cockpit when traversing busy waters such as Plymouth Port, with warships, guard boats, SERCO crew transfer hooligans and chain ferries to evade.

And I just might have some wrinkled signal flags and an elderly decode book gathering dust somewhere..... :ROFLMAO:
 
Mast head every time. Just make sure you put grease/Vaseline on all the connections before you make them to keep the water out and then add self amalgamating tape etc as belt and braces. Then get yourself an emergency antenna you can stick in the boat hook and hold up. (That threat will make sure the main antenna never fails?)
 
zoidberg said:
Yes, I know the preferred position is at the masthead, and I know why. Yet, I've sailed on many boats with non-functioning VHF/RT 'cos of a dicky antenna coupling 'up there somewhere' which will be fixed 'sometime'.....

The other option is mounted on the pushpit rail, or on a stub secured there that lifts the antenna a couple of metres higher. At present, that's my favoured option, principally as it would be readily accessible for 'maintenance'.

I DO have two new good quality antennae and a long length of quality cox, courtesy of our friend and contributor SaltyDog. Also, my mast is down ATM.

Arguments pro and contra, please....?
Click to expand...
Got one at the mast head, the original when i bought it was shagged, I messed around for the reasons you talk about. I also had one on the pushpit, from a radio in the cockpit, again on the boat when i bought it. I finally replaced the masthead one. No discernable difference in performance in real life use. The only thing I did notice was that the gps with the mushroom below the antenna on the pushpit would reset when transmitting on full power, so a note of caution there.
 
zoidberg said:
If I don't have anything to say, I try not to say it.

I DO have a handheld, which is more efficient used in the cockpit when traversing busy waters such as Plymouth Port, with warships, guard boats, SERCO crew transfer hooligans and chain ferries to evade.

And I just might have some wrinkled signal flags and an elderly decode book gathering dust somewhere..... :ROFLMAO:
Click to expand...
I do notice that the two handed middle finger swivel signal is recognisable from a long distance!
 
zoidberg said:
Yes, I know the preferred position is at the masthead, and I know why. Yet, I've sailed on many boats with non-functioning VHF/RT 'cos of a dicky antenna coupling 'up there somewhere' which will be fixed 'sometime'.....

The other option is mounted on the pushpit rail, or on a stub secured there that lifts the antenna a couple of metres higher. At present, that's my favoured option, principally as it would be readily accessible for 'maintenance'.

I DO have two new good quality antennae and a long length of quality cox, courtesy of our friend and contributor SaltyDog. Also, my mast is down ATM.

Arguments pro and contra, please....?
Click to expand...


Both. Normally, VHF uses masthead and AIS stern gantry antenna. However, cables can be changed over at the chart table. So far have only done so to test (out of interest) the masthead antenna using the AIS set's antenna test function.

I prefer to buy pre-wired antenna with enough length to reach the instrument to reduce potential failure points.
 
You could fit a mob one , it would look great , 3 metre of pure fibre glass , you would look like a CB eeeeer.
 
I fitted a new masthead antenna last year as the original fell off!(It was a Metz antenna from Salty John) fitted with the screw connection on the base so fitted another make which screwed on and sealed with self amalgamating tape. Seems to work OK but rarely used as I have a hh for marina contact etc. I also have a spare antenna on a post at the stern with the end near the radio so easy to switch over if necessary.
 
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Phantomfil said:
You could fit a mob one , it would look great , 3 metre of pure fibre glass , you would look like a CB eeeeer.
Click to expand...
I sailed on a Freedom 40 with one of those. Carbon fibre masts not fitted for cables. Only trouble was some day sailing visitors found it a convenient hand hold. It didn't work too well afterwards.
 
I just removed an (AIS) aerial from the push pit because I got fed up of arriving at the boat to find it damaged (this time torn off) in my absence by yet another careless visitor to the berth next to me. No way would I take the risk of arriving with hopes of a sail to find the primary VHF aerial ripped out in some similar manner because it was mounted low. Mast head every time. Never had an issue with the aerial up there (touch wood) which is probably original (22 years old) and I haven’t had the mast down in nearly 10 years.
 
bluerm166 said:
What about EMF ?
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Pushpit mount will loose range due to lack of height but more so where the signal goes through rigging etc. as wires can act as receiving antenna and ground the signal. However, if the mast goes over the side it is probably still better than a handheld. Which is another plus for a two antenna installation.

When teaching radio operator courses I do not remember any warnings about safe distance from a transmitting VHF antenna, but there were serious warnings to keep away for transmitting MF/HF antennas. Perhaps someone can correct me regarding VHF antenna safety if need be. The base of my stern antenna is about four metres above the deck so I am not too worried even if I had to transmit at full VHF power.
 
Safety of a marine VHF to people touching antenna while transmitting is not such a concern at max 25 watt power.
On my trailer sailor I have avoided any wiring to mast because of hassle when lowering mast (every winter) . My push pit is somewhat home made in that there is a post at corner. This extends another .5 metre above the rail. I ran the coax up this tube with braid connected to the top of the tube. A 17 inch piece of 4mm ss rod is mounted in insulation in the top of the post. The end of the ss is flattened with a hole drilled to take a bolt and lug to coax centre. it has worked very well for many years. Never any concern with range for my kind of sailing. The post incidentally is helpful as a hand hold when using stern ladder climbing from water.
Now there is no doubt a mast top antenna is best for range. But mine is reliable. I believe much better than a hand held radio.
So much depends on range OP needs. Perhaps he should consider both mast head and stern rail mounted with both cables available for selection at radio. Plus an obviouschoice for AIS. You can just see it in this photo. A bit bent. Gap in stern rail is to aid boarding from water. ol'willIMG_9568.jpeg
 
emf-calculator
You are obliged to check what may be an exceptional risk to 'the public' and I believe carry the calculation with the ships licence as we do.
Seems that an unusual combination of events might be more hazardous to a skipper or crew where the antenna is on the pushpit and the radio operator is transmitting near constantly at 25 watts- say in an offfshore crisis -from a fixed radio in /adjacent the stern cockpit ,or an incapacitated person is in the stern cabin ,underneath the antenna.
 
srm said:
Pushpit mount will loose range due to lack of height but more so where the signal goes through rigging etc. as wires can act as receiving antenna and ground the signal. However, if the mast goes over the side it is probably still better than a handheld. Which is another plus for a two antenna installation.

When teaching radio operator courses I do not remember any warnings about safe distance from a transmitting VHF antenna, but there were serious warnings to keep away for transmitting MF/HF antennas. Perhaps someone can correct me regarding VHF antenna safety if need be. The base of my stern antenna is about four metres above the deck so I am not too worried even if I had to transmit at full VHF power.
Click to expand...
We have a VHF by the chart table and dedicated antenna on the main mast of our ketch. In addition we have a cockpit mounted vhf and a dedicated antenna on the mizzen mast. In addition there is an AIS antenna also on the mizzen mast. Everything is fed from seperate power supplies. I think we have it covered😄
 
Fit one at mast head, then to guard against a dismasting when you will surely need urgent assistance or more mundanely guard against connection failure at mast head at a time or place when ascending the mast is not practical, fit one on the pushpit. Ideally a half or full wave length one as they give a bit more gain and extra height not an issue there - much much better than a handheld with its truncated aerial. Changeover at radio plug easy peasy if mast one not working. I could tell if my mast head connection was playing up by AIS receiver suddenly only showing boats moderately close to hand and weather forecast unusually blurred. If mast has fallen down dont bother with that check

Pushpit one good for at least 5 miles on mine but poor at 15 miles
 
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